Variation of the aerosol optical depth at the ARM CART site

Atmospheric aerosols are an important factor in the global radiation budget and greenhouse warming effect. Aerosols contribute to atmospheric pollution and degradation of visibility. In an effort to better characterize the variations in the columnar aerosol loading, the aerosol optical depth (AOD) has been computed for five of the Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) Cloud and Radiation Testbed (CART) facilities. Characterization of the AOD shows clear evidence that the spatial and temporal variations exist at a much finer scale than those of the CART site. The AOD measurements are indicators of atmospheric pollution and reduced visibility, and are used as inputs to radiative transfer models and research-grade Global Climate Models (GCM). The significant variations of the sub-GCM grid AOD cannot be ignored if the GCM are to be used to accurately predict future climate change.